Hydrogen bond relaxation dynamics and the associated symmetric, volumetric, vibronic, and phase transitional anomalies of frozen H2O under compression
Abstract
Coulomb repulsion between the unevenly-bounded bonding "-" and nonbonding ":" electron pairs in the "O2- : H+/p-O2-" hydrogen-bond is found to originate the anomalies of low-compressibility, phonon relaxation dynamics, proton symmetrization in the hydrogen-bond, and the change of the critical temperature for the VIII-VII phase transition of ice under compression. The resultant force of the compression, the repulsion, and the uneven binding strength of the electron pairs make the softer intermolecular "O2- : H+/p" nonbonding lone pair be highly compressed and stiffened but the stiffer intramolecular "H+/p-O2-" bond be elongated and softened. Consequently, the softer nonbond phonons (< 400 cm-1) are stiffened and the stiffer bond phonons (> 3000 cm-1) are softened upon compression. The nonbond compression and the real bond elongation results in the O2--H+/p : O2- symmetrization and the low compressibility of ice. Findings should form the starting point to unveil the physical anomalies of H2O under various stimuli.
- Publication:
-
arXiv e-prints
- Pub Date:
- October 2011
- arXiv:
- arXiv:1110.0075
- Bibcode:
- 2011arXiv1110.0075S
- Keywords:
-
- Condensed Matter - Other Condensed Matter;
- Physics - Chemical Physics
- E-Print:
- in sequence with arxiv.org/abs/1109.3958: H2O upon cooling from 298 to 98 K